Dose escalation of a phase 1b/2 study of modakafusp alfa, an immune-targeting attenuated cytokine, in patients (pts) with metastatic solid tumors

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Background: Modakafusp alfa (TAK-573) is a first-in-class immune-targeting attenuated cytokine designed to deliver attenuated interferon alpha-2b (IFNα2b) moieties to CD38-expressing cells. It consists of two attenuated IFNα2b molecules genetically fused to the Fc portion of a humanized, anti-CD38, IgG4 monoclonal antibody. Specificity for CD38 and reduced IFN receptor binding affinity of the attenuated IFNα2b molecules significantly reduces the potential for off-target binding and toxicity. Modakafusp alfa has demonstrated immune cell activation and antitumor activities in preclinical mouse models, including tumor models that do not express CD38, and has shown strong clinical responses and immune activation in pts with refractory/relapsed multiple myeloma. The dose-escalation phase of this phase 1b/2 study (NCT04157517) investigated safety, pharmacokinetics, immunogenicity, pharmacodynamics (PD), and preliminary efficacy of modakafusp alfa in metastatic solid tumors. Methods: Adult pts with advanced/metastatic solid tumors received modakafusp alfa IV on day 1 of a 21-day cycle (Q3W). Dose escalation started at 0.1 mg/kg and proceeded based on cycle 1 safety data via a Bayesian model with overdose control principles. Results: Twenty-one pts were dosed in the escalation phase at 0.1 (n = 3), 0.2 (n = 3), 0.4 (n = 3), 0.75 (n = 3), 1.0 (n = 3), and 1.5 mg/kg (n = 6) Q3W; median age 63 y (range 42–80); male 57.1%; GI malignancies 71.4%; median prior lines of therapy 3 (range 2–7). Two pts had dose-limiting toxicities in cycle 1 at 1.5 mg/kg; 1 pt with baseline bone infiltration had grade 4 thrombocytopenia and 1 pt had grade 3 confusion. As of Nov 2021, across all doses, pts received a median of 2 treatment cycles (range 1–11). Modakafusp alfa treatment-related adverse events (TRAEs) reported in 81% of pts included infusion-related reactions (52.4%), chills (47.6%), and nausea (33.3%). Grade ≥3 TRAEs reported in 42.9% of pts included neutropenia (14.3%) and hypertension (9.5%). There was a greater than dose proportional exposure increase in the dose range 0.1–1.5 mg/kg, with no exposure accumulation after Q3W dosing. Incidence rate of post-treatment anti-drug antibody (ADA) was 100%. PD data suggested saturation of peak IFN pathway modulation at ≥0.2 mg/kg in the peripheral blood with duration of modulation increasing with dose. Among the 14 response-evaluable pts, 7 had best response of stable disease, including 1 with cutaneous melanoma who had 21% target lesion reduction. Conclusions: Modakafusp alfa had a manageable safety profile in the dose range 0.1–1.5 mg/kg in pts with solid tumors. Proof of mechanism was validated. The recommended phase 2 dose was determined as 1.0 mg/kg Q3W based on assessment of holistic data and will be tested in combination with a checkpoint inhibitor in selected tumor types. Characterization of ADA and its impact is ongoing. Clinical trial information: NCT04157517.

Recommended phase 2 dose (RP2D) of HB-200 arenavirus-based cancer immunotherapies in patients with HPV16+ cancers

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Background: Treatment options are limited for patients with recurrent or metastatic human papillomavirus 16 positive (HPV16+) cancers. Generation and maintenance of HPV16+ cancers requires stable expression of HPV16-specific E7 and E6 oncoproteins, which are also a source of tumor-specific immunogenic neoantigens. HB-201 and HB-202 are replicating live-attenuated vectors based on lymphocytic choriomeningitis virus and Pichinde virus, respectively, which express the same non-oncogenic HPV16 E7E6 fusion protein and infect antigen presenting cells to induce tumor-specific T cell responses. The Phase 1 part of this study of HB-200 therapy (HB-201 single-vector therapy and HB-202/HB-201 two-vector alternating therapy) was conducted to determine RP2D for further exploration alone or in combination with pembrolizumab. Methods: The Phase 1 part used a 3+3 dose escalation design with up to 3 dose levels (DLs) of HB-201 and 4 DLs of HB-202/HB-201 explored. Patients with HPV16+ head and neck squamous cell carcinoma (HNSCC) or with other HPV16+ cancers were evaluated. Safety, tolerability, immunogenicity, and preliminary antitumor activity by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 or immune RECIST were assessed to determine RP2D. Results: As of January 2022, 65 patients with a median of 3 prior anticancer treatments have been enrolled in the Phase 1 part of the study. All had HPV16+ confirmed genotype; the most common primary site was oropharynx, followed by anal and cervix. Adverse events were generally mild or moderate. For HB-201, 3 DLs, 2 dosing schedules and 2 administration routes were assessed across 40 patients. At DL3 of HB-201 administered intravenously (IV), dose-limiting toxicity (DLT) occurred in 1/6 patients in the HNSCC group (Grade 4 encephalopathy, fully recovered) and 1/2 patients in the non-HNSCC group (Grade 3 rash, fully recovered). Preliminary safety, efficacy, and immunogenicity data support IV injection of DL3 (5 × 107 units) every 3 weeks (Q3W) as the RP2D for HB-201 single-vector therapy. For HB-202/HB-201, 4 DLs and 2 administration routes were assessed across 25 patients. At DL4 of HB-202/HB-201 IV, 1/5 subjects in the HNSCC group reported a DLT (Grade 4 hepatitis, recovering at time of discontinuation). RP2D for HB-202/HB-201 will be determined in the very near future. Tumor control, including partial response, have been observed in subjects treated with either HB-201 or HB-202/HB-201 as monotherapy. Conclusions: HB-201 and HB-202/HB-201 were generally well tolerated and showed preliminary antitumor activity in heavily pre-treated patients with HPV16+ solid tumors. DL3 was selected as RP2D for HB-201 monotherapy. In the Phase 2 part of the study a combination of HB-201 at 5 × 106 units IV Q3W with pembrolizumab is being tested in HPV16+ HNSCC patients. Clinical trial information: NCT04180215.

Abstract LB041: THOR-707 (SAR444245), a novel not-alpha IL-2 as monotherapy and in combination with pembrolizumab in advanced/metastatic solid tumors: Interim results from HAMMER, an open-label, multicenter phase 1/2 Study

THOR-707 (SAR444245) is a recombinant human IL-2 molecule that includes a PEG moiety irreversibly bound to a novel amino acid via click chemistry to block the alpha-binding domain while retaining near-native affinity for the beta/gamma subunits. In animal models, THOR-707 improved the anti-tumor benefits of aldesleukin, but without its severe side effects, both as single agent and combined with anti-PD1. Here we report safety, PK/PD, and preliminary anti-tumor activity for THOR-707 as monotherapy and combined with pembrolizumab in the ongoing HAMMER Phase 1/2 trial.

THOR-707 was administered via IV infusion as monotherapy Q2W (Cohort A), Q3W (Cohort B), or combined with pembrolizumab 200 mg IV Q3W (Cohort C); escalation follows a 3 + 3 schema to identify the maximum tolerated dose and/or the recommended Phase 2 dose.

As of 16 November 2020, 28 pts were enrolled: ECOG 0-1; median age 62 (37-76) yrs; median lines of prior therapies were 3 (1-9; 11 pts had prior anti-PD1). Most common tumor types: colorectal (n=5), melanoma (n=4). Cohort enrollment was A: 8 µg/kg (n=4); B: 8 µg/kg (n=4), 16 µg/kg (n=6), 24 µg/kg (n=7); C: 8 µg/kg (n=4), 16 µg/kg (n=3).

No dose-limiting toxicity (DLT) or vascular leak syndrome (VLS) was observed. Most common treatment-emergent adverse events (TEAEs) were flu-like symptoms (46.4%), fever (46.4%), vomiting/nausea (35.7%), chills (32.1%), following the first dose and resolved with standard supportive care. No cumulative toxicity, end organ toxicity, QTc prolongation, or other cardiac toxicity was observed. Grade (G) 3-4 related toxicities in B: 1 G3 rash (8 µg/kg); 1 G4 AST increase, 2 G3 increase in AST/ALT & 1 G4 decrease in lymphocytes (16 µg/kg); 2 G4 decrease in lymphocytes, 1 G4 CRS with G3 hypertension (led to discontinuation), and 1 G3 acute kidney injury (24 µg/kg); C: 1 G3 & 1G4 decrease in lymphocytes (16 µg/kg). CD8 cells (effector & memory) and NK cells increased in Cycle 1 by a median (range) respectively of 3.1 (1.04 - 5.91) and 7.93 (1.71 - 26.85) fold and were sustained until next cycle. There was no meaningful increase in CD4 Tregs or eosinophil counts (a marker of potential VLS), 1.89 (0.86- 5.36) and 1.77 (0.47- 3.65) fold. No anti-drug antibodies (IL-2 or PEG) and no meaningful IL-5 elevations were found. One IL-6 increase at 24 hrs (to 1,000 pg/mL) was observed. Half-life is ~ 10 hours.

Three pts have confirmed partial responses: 1 PD-1-naïve basal cell carcinoma; 1 head & neck squamous cell carcinoma with progression after a prior anti-PD-1, ongoing for 9+ mos in C (8 µg/kg); 1 squamous cellular carcinoma of unknown origin, unresponsive to prior anti-PD-1, ongoing for 3+ mos in B (24 µg/kg). Two pts had stable disease for 9 and 6 mos, respectively, with pancreatic (in A, 8 µg/kg) and prostate cancer (in B, 16 µg/kg); 11 pts remained on treatment for ≥5 cycles.

Preliminary encouraging results with THOR-707 monotherapy and in combination with pembrolizumab support IL-2 not-alpha preferential activity, validating preclinical models, with initial efficacy and a tolerable safety profile. Dose escalation continues. NCT04009681

Citation Format: Filip Janku, Raghad Abdul-Karim, Arun Azad, Johanna Bendell, Gerald Falchook, Hui K. Gan, Tira Tan, Judy S. Wang, Cheng Ean CHEE, Lina Ma, Jill Mooney, Neyssa Marina, Giovanni Abbadessa, Marcos Milla, Tarek Meniawy. THOR-707 (SAR444245), a novel not-alpha IL-2 as monotherapy and in combination with pembrolizumab in advanced/metastatic solid tumors: Interim results from HAMMER, an open-label, multicenter phase 1/2 Study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB041.

Abstract CT166: A Phase I/II, open-label, two part study of GSK3359609 in combination with tremelimumab in participants with selected, advanced solid tumors

Background: GSK3359609 (GSK609) is an inducible T cell co-stimulator (ICOS) agonist antibody and tremelimumab (treme) is a cytotoxic T-lymphocyte-antigen 4 (CTLA-4) antagonist antibody. Nonclinical and clinical studies have shown that ICOS expression on T cells is upregulated after anti-CTLA-4 treatment (tx). ICOS+ T cells have a positive association with overall survival (OS) in treme treated chemotherapy-resistant malignant mesothelioma and melanoma patients (pts). Therefore, the combination of these 2 drugs may provide greater antitumoral response than either drug alone (Coutzac C: AACR 2019 meeting abstract).

Methods: This is a Phase I/II, open-label, 2-part study. In Part 1, N=~24 pts will be enrolled. The study is designed to assess treme starting at 75 mg followed by GSK609 starting at 8 mg. At dose level (DL) 1, one pt who will receive the lowest doses of both drugs will be enrolled. If no dose limiting toxicity (DLT) is observed in the DLT observation period of 28 days, then 1-3 pts will be enrolled in DL2 - DL6 in a zone-based fashion (zones include the DLs with the next highest dose of one of the two drugs - 2DL are included in each zone in this study) with different dose combinations of the drugs being evaluated. The dose of 1 of the 2 drugs will be escalated with each new DL up to the highest dose of each. If ≥ grade 2 tx-related AEs occur at DL1 or 2, additional pts will be enrolled to collect more safety information. If DLTs are observed, the bivariate Continual Reassessment Method (CRM) model will be used to guide dose recommendations. The primary objective of Part 1 will be to assess safety. Additional pts may be enrolled in Part 1 to further evaluate pharmacokinetics/pharmacodynamics (PK/PD). Part 2 is a randomized expansion enrolling recurrent/metastatic head and neck squamous cell carcinoma pts who have disease progression after platinum chemotherapy and anti-programmed death receptor protein-1 (PD-1)/anti-programmed death-ligand 1 (PD-L1) therapy, in combination or separately. Pts may not have had ≥4 lines of prior tx in either Part 1 or 2. In Part 2, pts will be randomized 2:1 to the doses of GSK609 and treme (n=60) selected from Part 1 or to the Investigator’s choice of SOC single-agent therapy (paclitaxel, docetaxel or cetuximab) (n=30). The primary objective in Part 2 is to evaluate overall survival and the primary analysis is to perform Bayesian predictive probability of success for a future hypothetical Phase III study based on survival data. Secondary endpoints include safety, ORR, PFS, DOR, and PK while pharmacodynamic and other biomarker analyses constitute exploratory endpoints. Pts will be treated for up to 2 years with survival follow-up for up to 2 years post-tx. This study has enrolled 1 pt. Study NCT03693612 funded by GSK.

Citation Format: Aaron Hansen, Raghad Abdul-Karim, Naiyer Rizvi, Danny Rischen, John Hilton, Zujun Li, Patrick Ott, Natalie Karpinich-Fedoriw, Sapna Yadavilli, Xiaowei Wang, Laurel Adams, Melody Wyres, Charles Ferte, Marc Ballas, Axel Hoos, Daniel Zandberg. A Phase I/II, open-label, two part study of GSK3359609 in combination with tremelimumab in participants with selected, advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT166.

Levamisole-induced vasculitis

Levamisole-contaminated cocaine is an increasingly reported cause of a syndrome characterized by vasculitic skin lesions and immunologic abnormalities. With approximately 70% of cocaine in the United States now contaminated with levamisole, the incidence of this syndrome is likely to increase. We report two cases of this syndrome and review its clinical presentation, course, and prognosis.

Effect of oestrogen on fetal survival in the rabbit

Pregnant rabbits (Day 18) were treated i.m. for 3 days with 10 microgram oestradiol 17beta/kg. The number of dead fetuses was significantly greater than in the control animals but corpus luteum weight and peripheral progesterone concentrations were not affected. Fetal death was therefore not due to luteolysis.